Re: [PATCH v3] gdb: z80: Fix endless loop in frame unwinder and validate saved register types

[Ronald Hecht <ronald.hecht@gmx.de>]

Hi Kevin,

Thank you for the review and the approval! Since I do not have write 
access to the GDB repository, could you please push the patch on my behalf?

Best regards,
Ronald

On 6/20/26 22:11, Kevin Buettner wrote:
> Hi Ronald,
>
> This looks great!  Thanks for making the changes I requested.
>
> On Mon, 15 Jun 2026 09:04:01 +0200
> Ronald Hecht <ronald.hecht@gmx.de> wrote:
>
>> In z80_frame_unwind_cache, the loop scanning for the frame base pointer
>> (for (;; ++sp)) could run into an endless loop or scan too far if the
>> termination condition (sp < this_base) was not met due to corrupted
>> or unexpected stack layouts. This patch introduces a loop_count to
>> limit the scan to a maximum of 2 * addr_len iterations.
>>
>> Additionally, when iterating through saved registers to adjust their
>> offsets into concrete addresses, the code now explicitly checks if
>> the register actually holds an address using is_addr() before calling
>> addr(). This prevents potential assertions or undefined behavior for
>> registers that do not contain valid address data.
>>
>> gdb/ChangeLog:
>>
>> 	* z80-tdep.c (z80_frame_unwind_cache): Limit stack scanning
>> 	to 2 * addr_len iterations to prevent endless loops. Check
>> 	is_addr() before adjusting saved register addresses.
> The ChangeLog entry isn't required, but there's no harm in having it in
> the commit log.  Regardless, don't add it to any ChangeLog files prior
> to pushing it.
>
> Approved-By: Kevin Buettner <kevinb@redhat.com>
>